X0609 4 2026-05-14 0001493594 MACOM Technology Solutions Holdings, Inc. MTSI 0001239366 CHUNG PETER Y false C/O SUMMIT PARTNERS 222 BERKELEY STREET, 18TH FLOOR BOSTON MA 02116 true false false false 0 Common Stock 2026-05-14 4 S 0 43268 378.1992 D 6781 I See Remarks The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $377.80 to $379.44. The Reporting Person undertakes to provide to the Issuer, any shareholder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. The 6,781 shares and restricted stock units are held in the name of Mr. Chung, which are held for the benefit of Summit Partners, L.P. Mr. Chung holds any Common Stock and restricted stock units for the benefit of Summit Partners, L.P. which he has empowered to determine when the underlying shares will be sold and which is entitled to the proceeds of any such sales. Summit Partners, L.P., through a two-person Investment Committee, responsible for voting and investment decisions with respect to the Issuer, currently composed of Scott C. Collins and Peter Y. Chung, has voting and dispositive authority over the shares and restricted stock units reported herein and therefore may be deemed to beneficially own such shares. Summit Partners, L.P., Mr. Collins and Mr. Chung disclaim beneficial ownership of the shares of common stock and the restricted stock units, except to the extent of their pecuniary interest therein. Adam H. Hennessey, POA for Peter Y. Chung 2026-05-18